质谱同位素稀释法测定粉煤灰标样中痕量铀和钍

The Determination of Trace Uranium and Thorium in Coal Fly Ash by Isotope Dilution Mass Spectrometric Method

本文以^(235)U和^(230)Th作稀释剂,用质谱同位素稀释法测定粉煤灰标样中痕量U和Th。其检出限分别为1.9×10^(-8)和2.4×10^(-9)g。该法测含U12.98ppm、含Th27.50ppm的粉煤灰试样时精密度均为1.9%。试样在550℃下灰化,然后用HF除硅,用HNO_3溶解残渣,萃淋树脂柱分离,U、Th淋洗液浓缩后用质谱仪测定。

A method for the separation and determin ation of trace U and Th in coal fly ash by isotope dilution mass spectrometry has been studied. ^(235)U and ^(230)Th were used as spikes. A simple procedure for sample prepara- tion was proposed. The main agents were purified by CL-5209 extractant containing resin, a low blank and high sensitivity were obtained. The detection limits are 1.9×10^(-8)g for U and 2.4×10^(-9)g for Th. The coefficient of variation is 1.9% both U and Th at a level of 12.98 ppm U and 27.50ppm Th. A model ZHT-05A single focusing mass spectrometer with solid ion source was used for all mass spectrometric measurements.